A Biologic Comparison of Two Strains of <i>Herpesvirus Hominis</i>

Abstract

Summary Two strains of Herpesvirus hominis which differ primarily in the cytopathic effects they induce in various host cells in tissue culture have been described. One strain (GC) causes the formation of syncytial giant cells, whereas the other strain (P) produces rounding and piling up of the cells with a few small giant cells but no syncytia. A number of other characteristics of these two strains were studied. Each was able to grow to the same titer in several lines of cultured cells. Their rates of multiplication were similar and new virus appeared in the medium between 5 and 7 hr after inoculation. Each was similarly inactivated by heat, the half life being 1 hr and 30 min at 37°C and 3 hr and 48 min at 30–31°C. Each was inactivated by u.v. light at the same rate with a half life of 7 sec. There was no difference in the rate of adsorption or penetration, 87% and 91% being adsorbed and 100% and 88% of the adsorbed P and GC strains, respectively, having penetrated within 2 hr at 37°C. Both strains were equally infective for mice and rabbits. They did not differ in antigenicity. The electronmicroscope showed particles of identical size (medians 154 mμ and 157 mμ respectively). G6P dehydrogenase and hexokinase activities in cells infected with either strain were increased over controls at 12 hr after inoculation, indicating increased permeability of cell membranes. At 3 and 6 hr after inoculation the hexokinase activity in GC infected cells differed from that in P infected cells. Some observations have been made on the toxic effect of neutral red on RK cells.